Common Organic Compound Found in Many Household Products May Pose Health Risk to Breast Cells

Written by Administrator

Bisphenol A, a chemical that leaches into food and beverages from many consumer products, causes normal, non-cancerous human breast cells to express genes characteristic of aggressive breast cancer cells. That's the finding of a "Priority Report" in the latest issue of the journal Cancer Research, the official journal of The American Association for Cancer Research.

This new information about bisphenol A (BPA) is timely because the State of California is currently considering placing BPA on the Prop 65 list of hazardous chemicals, and State Senator Fiona Ma has proposed legislation that would ban BPA in products used by children.

The study was done by researchers at the California Pacific Medical Center Research Institute, in collaboration with the Stanford Genome Technology Center.

The findings are significant because BPA is found in many plastic water bottles, in plastic baby bottles, in the lining in food cans, as well as in sealants used by dentists to protect teeth.

"This is a very common compound that most of us are exposed to on a regular basis, often without even being aware of it," says William Goodson, M.D., Senior Clinical Research Scientist at the Institute and lead researcher on the study. "If it's true that exposure to BPA can cause normal, non-cancerous human breast cells to behave in ways that are more characteristic of aggressive breast cancer cells, this is very worrying."

The researchers did needle aspirations on eight consented women at high risk of breast cancer, or its recurrence, to remove a small sample of non-cancerous cells. The cells were exposed to BPA in the lab and then analyzed to see if the exposure had altered, in any way, the gene expression of the cells.

"We screened 40,000 genes in normal human cells that had been exposed to BPA and found a striking increase in the sets of genes that promote cell division, increase cell metabolism, and increase resistance to drugs that usually kill cancer cells, and prevent cells from developing to their normal mature forms," says says Shanaz Dairkee, Ph.D., the Principal Investigator of this California State-funded project at CPMCRI, and the co-author of the study. "Breast cancer patients with this kind of gene expression tend to have a higher recurrence than other patients, and they have a worse survival rate."

The researchers chose to focus on BPA because it is a common compound with a controversial reputation. BPA acts like an estrogen, and in animal studies has been shown to have carcinogenic effects including increasing the risk of breast and prostate cancer, as well as reducing sperm-count and impacting the immune system. A study by the Centers for Disease Control and Prevention in 2004 found that 95 percent of people tested had traces of BPA in their urine, with women having higher blood concentrations of BPA then men, and children having higher concentrations than adults.

"Our use of fresh cells for short term cultures in this research is unusual in medical research," emphasizes Dr. Goodson, "which makes the results especially useful because this is the closest we can ethically get to studying the effects of giving BPA directly to living people. Our cells are much closer to normal tissue than usual cell culture techniques which use cells that have been growing in laboratories for months or even years."

"Although the study itself does not prove that BPA causes malignancy, the observation that exposure to BPA altered the expression of genes in human breast cells deserves further investigation," says Wenzhong Xiao, Ph.D., a senior researcher at Stanford Genome Technology Center and a co-author of the study.

The concentration of BPA that the researchers tested was very low (less than one tenth of a millionth of a gram per milliliter), but this concentration of BPA has been found in blood from pregnant women in both the United States and Germany.

About Breast Cancer

Breast
cancer is a malignant (cancerous) tumor that starts from cells of the breast.
The disease occurs mostly in women, but men can get breast cancer too. In the
U.S., it affects one in eight women. There are many types of breast cancer,
though some of them are very rare. Sometimes a breast tumor can be a
combination of these types and to have a mixture of invasive and in situ
cancer. The most common types of breast
cancer are:

Ductal carcinoma in situ (DCIS): This
is the most common type of non-invasive breast cancer (85 - 90% of all
cases). DCIS means that the cancer is only in the ducts. It has not spread
through the walls of the ducts into the tissue of the breast. Nearly all
women with cancer at this stage can be cured. Often the best way to find
DCIS early is with a mammogram.

Lobular carcinoma in situ (LCIS): This
condition which occurs in approximately 8% of all cases, begins in the
milk-making glands but does not go through the wall of the lobules.
Although not a true cancer, having LCIS increases a woman's risk of
getting cancer later. For this reason, it's important that women with LCIS
to follow the screening guidelines for breast cancer.

Less common
are:

Inflammatory breast cancer (IBC): This
uncommon type of invasive breast cancer accounts for about 1% to 3% of all
breast cancers. Usually there is no single lump or tumor. Instead,
inflammatory breast cancer (IBC) makes the skin of the breast look red and
feel warm. It also gives the skin a thick, pitted appearance that looks a
lot like an orange peel. Doctors now know that these changes are not
caused by inflammation or infection, but by cancer cells blocking lymph
vessels in the skin. The breast may become larger, firmer, tender, or
itchy. IBC is often mistaken for an infection in its early stages. Because
there is no defined lump, it may not appear on a mammogram, which may make
it even harder to catch it early. It usually has a higher chance of
spreading and a worse outlook than invasive ductal or lobular cancer.

Paget's disease of the nipple. Paget's
disease of the nipple or breast is a rare type of breast cancer, which can
occur in women and men. It shows up in and around the nipple, and usually
signals the presence of breast cancer beneath the skin. Most cases are
found in menopausal women, but can also appear in women that are as young
as 20. Early stages symptoms
include redness, scaly and flaky, and
mild irritation of nipple
skin. Advanced stages may include: tingling in nipple skin, very sensitive
skin on the nipple, burning or painful nipple skin, ooze or bloody
discharge from the nipple (not milk), itchiness that doesn't respond to
creams, nipple retraction (pulls into the breast), scaly rash on areola
skin, and/or breast lump beneath the affected skin.

Symptoms of
breast cancer may include:

a
lump or a thickening in the breast or in the armpit. Note Most breast
lumps are benign (be-nine); that is, they are not cancer. Benign
breast tumors are abnormal growths, but they do not spread outside of the
breast and they are not life threatening. But some benign breast lumps can
increase a woman's risk of getting breast cancer. Most lumps turn out to
be caused by fibrocystic (fi-bro-sis-tik) changes. Cysts are
fluid-filled sacs. Fibrosis is the formation of scar-like tissue. Such
changes can cause breast swelling and pain. The breasts may feel lumpy,
and sometimes there is a clear or slightly cloudy nipple discharge.

a
change of size or shape of the mature breast

fluid
(not milk) leaking from the nipple

a
change of size or shape of the nipple

a
change of color or texture of the nipple or the areola, or of the skin of
the breast itself (dimples, puckers, rash)